/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/*
     File added by Alan Buckley (alan_baa@hotmail.com) for RISC OS compatability
	 27 March 2003

     Implements Sprite plotting code for wimp display.window
*/

#include "kernel.h"
#include "swis.h"

#include "SDL_stdinc.h"
#include "SDL_riscosvideo.h"

extern void WIMP_ReadModeInfo(_THIS);

void WIMP_PaletteChanged(_THIS);


/* Create sprite buffer for screen */

unsigned char *
WIMP_CreateBuffer(int width, int height, int bpp)
{
    int size;
    char sprite_name[12] = "display";
    unsigned char *buffer;
    _kernel_swi_regs regs;
    int bytesPerPixel;
    int bytesPerRow;
    int offsetToSpriteData = 60;

    switch (bpp) {
    case 32:
        bytesPerPixel = 4;
        break;
    case 16:
        bytesPerPixel = 2;
        break;
    case 8:
        bytesPerPixel = 1;
        offsetToSpriteData += 2048;     /* Add in size of palette */
        break;
    default:
        return NULL;
        break;
    }

    bytesPerRow = bytesPerPixel * width;

    if ((bytesPerRow & 3) != 0) {
        bytesPerRow += 4 - (bytesPerRow & 3);
    }
    size = bytesPerRow * height;

    buffer = SDL_malloc((size_t) size + offsetToSpriteData);
    if (!buffer)
        return NULL;

    /* Initialise a sprite area */

    *(unsigned int *) buffer = size + offsetToSpriteData;
    *(unsigned int *) (buffer + 8) = 16;

    regs.r[0] = 256 + 9;
    regs.r[1] = (unsigned int) buffer;
    _kernel_swi(OS_SpriteOp, &regs, &regs);

    regs.r[0] = 256 + 15;
    regs.r[1] = (unsigned int) buffer;
    regs.r[2] = (unsigned int) &sprite_name;
    regs.r[3] = 0;              /* Palette flag: 0 = no palette */
    regs.r[4] = width;
    regs.r[5] = height;
    if (bpp == 8) {
        /* Use old style mode number */
        regs.r[6] = 28;         /* 8bpp 90x90dpi */
    } else {
        regs.r[6] = (((bpp == 16) ? 5 : 6) << 27)       /* Type 6 = 32bpp sprite, 5 = 16bpp sprite */
            |(90 << 14)         /* Vertical dpi */
            |(90 << 1)          /* Horizontal dpi */
            |1;                 /* Marker to distinguish between mode selectors and sprite modes */
    }
    if (_kernel_swi(OS_SpriteOp, &regs, &regs) == NULL) {
        if (bpp == 8) {
            /* Modify sprite to take into account 256 colour palette */
            int *sprite = (int *) (buffer + 16);
            /* Adjust sprite offsets */
            sprite[0] += 2048;
            sprite[8] += 2048;
            sprite[9] += 2048;
            /* Adjust sprite area next free pointer */
            (*(int *) (buffer + 12)) += 2048;

            /* Don't need to set up palette as SDL sets up the default
               256 colour palette */
/*          {
             int *pal = sprite + 11;
             unsigned int j;
             unsigned int entry;
             for (j = 0; j < 255; j++)
             {
                entry = (j << 24) | (j << 16) | (j << 8);
                *pal++ = entry;
                *pal++ = entry;
             }
          }
*/
        }
    } else {
        SDL_free(buffer);
        buffer = NULL;
    }

    return buffer;
}


/* Setup translation buffers for the sprite plotting */

void
WIMP_SetupPlotInfo(_THIS)
{
    _kernel_swi_regs regs;
    int *sprite = ((int *) this->hidden->bank[1]) + 4;

    regs.r[0] = (unsigned int) this->hidden->bank[1];
    regs.r[1] = (unsigned int) sprite;
    regs.r[2] = -1;             /* Current mode */
    regs.r[3] = -1;             /* Current palette */
    regs.r[4] = 0;              /* Get size of buffer */
    regs.r[5] = 1 | 2 | 16;     /* R1 - pointer to sprite and can use full palette words */
    regs.r[6] = 0;
    regs.r[7] = 0;

    if (this->hidden->pixtrans)
        SDL_free(this->hidden->pixtrans);
    this->hidden->pixtrans = 0;

    /* Get the size required for the buffer */
    _kernel_swi(ColourTrans_GenerateTable, &regs, &regs);
    if (regs.r[4]) {
        this->hidden->pixtrans = SDL_malloc(regs.r[4]);

        regs.r[4] = (unsigned int) this->hidden->pixtrans;
        /* Actually read the buffer */
        _kernel_swi(ColourTrans_GenerateTable, &regs, &regs);
    }
}

/* Plot the sprite in the given context */
void
WIMP_PlotSprite(_THIS, int x, int y)
{
    _kernel_swi_regs regs;
    _kernel_oserror *err;

    regs.r[0] = 52 + 512;
    regs.r[1] = (unsigned int) this->hidden->bank[1];
    regs.r[2] = (unsigned int) this->hidden->bank[1] + 16;
    regs.r[3] = x;
    regs.r[4] = y;
    regs.r[5] = 0 | 32;         /* Overwrite screen and pixtrans contains wide colour entries */
    regs.r[6] = 0;              /* No scale factors i.e. 1:1 */
    regs.r[7] = (int) this->hidden->pixtrans;

    if ((err = _kernel_swi(OS_SpriteOp, &regs, &regs)) != 0) {
        int *p = (int *) this->hidden->pixtrans;
        printf("OS_SpriteOp failed \n%s\n", err->errmess);
        printf("pixtrans %d\n", (int) this->hidden->pixtrans);
        printf("%x %x %x\n", p[0], p[1], p[2]);
    }
}


/* Wimp mode has changes so update colour mapping and pixel sizes 
   of windows and the sprites they plot */

void
WIMP_ModeChanged(_THIS)
{
    int oldXeig = this->hidden->xeig;
    int oldYeig = this->hidden->yeig;

    WIMP_ReadModeInfo(this);

    if (oldXeig == this->hidden->xeig && oldYeig == this->hidden->yeig) {
        /* Only need to update the palette */
        WIMP_PaletteChanged(this);
    } else {
        _kernel_swi_regs regs;
        int window_state[9];
        int extent[4];
        int currWidth, currHeight;
        int newWidth, newHeight;

        /* Need to resize windows and update the palette */
        WIMP_SetupPlotInfo(this);


        window_state[0] = this->hidden->window_handle;
        regs.r[1] = (unsigned int) window_state;
        _kernel_swi(Wimp_GetWindowState, &regs, &regs);

        currWidth = window_state[3] - window_state[1];
        currHeight = window_state[4] - window_state[2];

        newWidth = (currWidth >> oldXeig) << this->hidden->xeig;
        newHeight = (currHeight >> oldYeig) << this->hidden->yeig;
        /* Need to avoid extent getting too small for visible part
           of window */
        extent[0] = 0;
        if (currHeight <= newHeight) {
            extent[1] = -newHeight;
        } else {
            extent[1] = -currHeight;
        }
        if (currWidth <= newWidth) {
            extent[2] = newWidth;
        } else {
            extent[2] = currWidth;
        }
        extent[3] = 0;

        regs.r[0] = this->hidden->window_handle;
        regs.r[1] = (int) extent;
        _kernel_swi(Wimp_SetExtent, &regs, &regs);

        /*TODO: May need to set flag to resize window on next open */
    }
}

/* Palette has changed so update palettes used for windows sprites */

void
WIMP_PaletteChanged(_THIS)
{
    WIMP_SetupPlotInfo(this);
}

/* vi: set ts=4 sw=4 expandtab: */
